Use of car and bite technology coupled with an ScFv from an antibody against human thymidine kinase 1 to specifically target tumors

ABSTRACT

Modified T-cells have paratopes against human TK1 epitopes, are made by producing monoclonal antibodies that are specific to TK1, creating chimeric antigen receptors (CARs) by fusion of the single-chain variable fragments (scFv) of the monoclonal antibodies to T-cell signalling domains, and transducing the CARs to the T-cells.

CROSS REFERENCE TO RELATED APPLICATIONS

Priority is claimed from U.S. patent application Ser. No. 15/161,045,filed May 20, 2016, now U.S. Pat. No. 10,434,153, issued Oct. 8, 2019,which itself claims priority from U.S. Provisional Patent Application62/164,524, filed 20 May 2015, and from U.S. Provisional PatentApplication 62/204,935, filed 14 Aug. 2015, which are herebyincorporated by reference.

BACKGROUND

Although efforts in cancer research have been ongoing for more than 20years, cancer still accounts for more deaths than heart disease inpersons younger than 85 years. Very little progress has been made in thepast 30 years to decrease cancer mortality rates and incidence rates. In2014, there will be an estimated 1,665,540 new cancer cases diagnosedand 585,720 cancer deaths in the US. Cancer remains the second mostcommon cause of death in the US, accounting to nearly 1 of every 4deaths. [1] It is accepted that while there has been some isolatedprogress with respect to a few types of cancers (breast, prostate,colon), overall, cancer researchers in the past 30 years have made verylittle headway against this devastating disease.

Although there has been very little progress, many novel chemotherapiesthat employ the use of specific antibodies are now showing promise inclinical trials. These new immunotherapies include the use of antibodiesand immune cell therapies, coupled with cytokine administration, thatare targeting specific tumor types and allowing significant progress inseveral cancer fields. Many of these chemotherapies target very specificsubtypes of cancer, such as treatments with Herceptin (an antibodytherapy) used in approximately 10% of breast cancers.

Antibodies against tumor associated epitopes, are proving useful in manytumor therapies but are limited to antigens presented on the cellsurface of tumors. Several antibodies have been identified and exploitedagainst multiple types of cancers using passive immunization. Notableexamples include rituximab (anti-CD20 for B-cell lymphomas) andtrastuzumab (anti-HER-2/neu for certain breast cancers). [6] Therapeuticantibodies have had success against tumors, eliciting bothcomplement-mediated responses and antibody-dependent cellularcytotoxicity (ADCC). However, administration of an anti-cancer antibodyas a monotherapy is rare, and these are often combined with moretraditional chemotherapy. [4]

However, unless researchers are able to identify a cancer specific yetuniversal therapy to target all cancers, progress in the fight againstcancer will also be limited. In the present study, we introduce thepotential for one such novel immunotherapy: Thymidine Kinase 1 (TK1), atumor biomarker known to be unregulated as an early event in virtuallyall types of major cancers.

Thymidine Kinase 1 (TK1) is a well-known nucleotide salvage pathwayenzyme that has largely been studied in the context of itsoverexpression in tumors. Since TK was initially popularized by itsexpression in the serum of cancer patients (sTK), its diagnostic andprognostic potential has been studied extensively. For example, severalstudies have demonstrated that sTK1 in many different cancer patients iselevated in a stage-like manner with a higher level of TK1 indicating amore advanced tumor. [12]

Other studies have investigated the prognostic potential of TK1. Onesuch study demonstrates that the TK1 levels in primary breast tumors canbe used to predict recurrence. Other exciting TK1 prognostic studiesshow significant reductions in sTK1 levels when patients respond totreatment while sTK1 levels continue to rise in patients who do notappear to respond to their treatment. It is also known that prior torecurrence, sTK1 levels begin to rise and in one study it was noted thatin some cases, by measuring sTK1 levels recurrence could be predicted“1-6 months before the onset of clinical symptoms.” Several otherstudies confirm the rich potential of TK1 as a diagnostic and prognosticindicator of cancer [13].

Although the diagnostic and prognostic potential of TK1 has been wellestablished, the therapeutic potential of TK1 remains veiled incomparison. While it is true that HSV-TK has been used in gene therapyand PET imaging utilizes TK to identify proliferating cancer cells, few,if any studies address the possibility of a TK1 immunotherapy. Perhapsthis is primarily because TK1 is a known cytosolic protein. We haverecently discovered that TK1 is expressed not only in cancer cells butalso on the surface membrane of all cancer types and is therefore a veryviable target for tumor immunotherapy.

T cells are capable of inducing potent anti-tumor responses, however, Tcells that would most efficiently respond to peptide-MHC epitopes on thesurface of tumors are often subjected to clonal tolerance or deletion,as many of these epitopes are very similar or identical toself-epitopes. T-cell therapies have involved genetic modification of Tcells in vitro by introduction of TCRs against tumor-associated T-cellepitopes. This strategy has shown promise, but various challengessurrounding T-cell epitopes in general, as well as potential mispairingof introduced TCR with endogenous TCR, remain [3]. To harness the powerof T cells in the fight against tumors, several methods have beendesigned that allow T cells to respond to traditional antibody epitopes.

Chimeric antigen receptors (CARs), consisting of extracellular antibodyfragments directed against a tumor epitope fused to intracellular T-cellsignaling domains, have been transduced into T cells, endowing them witha novel specificity toward a non-MHC restricted epitope[3]. Chimericantigen receptors (CARs) are recombinant receptors that provide bothsurface antigen-binding and T-cell-activating functions. A number ofCARs has been reported over the past decade, targeting an array of cellsurface tumor antigens. Their biologic functions have dramaticallychanged following the introduction of tripartite receptors comprising acostimulatory domain, termed second-generation CARs.

These have recently shown clinical benefit in patients treated withCD19-targeted autologous T cells. CARs may be combined withcostimulatory ligands, chimeric costimulatory receptors, or cytokines tofurther enhance T-cell potency, specificity, and safety. CARs representa new class of drugs with exciting potential for cancer immunotherapy.[3]

Artificial T cell receptors (also known as chimeric T cell receptors,chimeric immunoreceptors, chimeric antigen receptors (CARs)) areengineered receptors, which graft an arbitrary specificity onto animmune effector cell. Typically, these receptors are used to graft thespecificity of a monoclonal antibody onto a T cell; with transfer oftheir coding sequence facilitated by retroviral vectors.

Upon their expression in T lymphocytes, CARs direct potent, targetedimmune responses that have recently shown encouraging clinical outcomesin a subset of patients with B-cell malignancies. This applicationbrings together this new technology with our discovery that TK1 isexpressed on the surface of cancer cells, by using a specifically builtCAR that has an scFv from our anti human TK1 antibody to utilize thepotential of CARs and the TK1 technology to attack tumor cells in vivo.Our recent discovery that TK1 is found on the surface of cancer cellsand not normal cells allows the targeted application of CAR technologyspecific targeting TK1 surface expressing tumors.

The most common CAR formats currently being evaluated include a scFvtargeting domain linked to a spacer, trans membrane domain, andintracellular domains from the T-cell receptor CD3ζ subunit andco-stimulatory domains, such as CD28, OX40 or 4-1BB.21 CAR-basedstrategies continue to be pursued against a number of tumor-associatedepitopes. [4]. Results from recent clinical trials demonstrate theeffectiveness of CAR-transduced T cells targeted against the B cellepitope CD19 in achieving long-term remission from refractory chroniclymphocytic leukemia (CLL) when transferred as a monotherapy followinglymphodepleting chemotherapy[5].

Referring to FIG. 1 is shown a TK1 specific CAR T cell that recognizesTK1 as a target on cancer cells. In the ligand binding domain ectodomainis shown a signal peptide and an antigen recognition domain is usuallyan scFv. A spacer region links the antigen binding domain to thetransmembrane domain.

The transmembrane domain is a hydrophobic alpha helix that spans themembrane. Generally, the transmembrane domain from the most membraneproximal component of the endodomain is used.

After antigen recognition receptors cluster in the endodomain and asignal is transmitted to the cell. In an aspect of CARs, there is theintracellular domain from the CD3-zeta (CD3 ζ)-chain, which is theprimary transmitter of signals from endogenous T-cell receptors (TCRs).There may be added intracellular signaling domains from variouscostimulatory protein receptors, such as CD3-zeta and additionalco-stimulatory signaling. ZAP-70 also is part of the T cell receptor,and plays a critical role in T-cell signaling.

Another strategy to target T cells to precise antibody epitopes takesadvantage of a long-studied type of molecule called “bispecificantibody,” which links an anti-cancer antibody with an antibodyrecognizing CD3 subunits.

These have recently been termed BiTEs (bispecific T-cell engagers). Asingle-chain variable fragment (scFv) that binds a tumor epitope islinked to a second scFv that binds an invariant portion of the T-cellreceptor complex, resulting in activation and targeting of effector Tcells against the tumor epitope, regardless of the TCR-mediatedspecificity of the T cells. Evidence shows that these reagents areconsiderably more potent than antibodies against tumor cells alone.BiTEs have been constructed targeting more than ten tumor associatedepitopes, including blinatumomab against CD19 (for B cell leukemias),and MT-110 against EpCAM (for various adenocarcinomas an@d cancer stemcells), both being currently evaluated in clinical trials. Highrespon@se rates for relapse-free survival and elimination of minimalresidual disease were found in refractory acute lymphoblastic leukemia(ALL) patients receiving blinatumomab in clinical trials [6].

Referring to FIG. 2, BiTEs are fusion proteins consisting of twosingle-chain variable fragments (scFvs) of different antibodies, oramino acid sequences from four different genes, on a single peptidechain. One of the scFvs binds to T cells via the CD3 receptor, and theother to a tumor cell via a tumor specific molecule,

Like other bispecific antibodies, and unlike ordinary monoclonalantibodies,

BiTEs form a link between T cells and tumor cells. This causes T cellsto exert cytotoxic activity on tumor cells by producing proteins likeperforin and granzymes, independently of the presence of MHC I orco-stimulatory molecules. These proteins enter tumor cells and initiatethe cell's apoptosis. This action mimics physiological processesobserved during T cell attacks against tumor cells.

While both of these strategies have shown promising results, it is notyet clear under what conditions the CAR approach vs. the BiTE approachmight be preferred. The optimal utilization of this knowledge would bein the production of a chimeric antigen receptor (CAR), or BiTEsutilizing the power of a monoclonal antibody produced against human TK1coupled with the ability of T cells to destroy tumor cells. This is thebasis of this application. Use your figure which is too general and makeit more specific

FIG. 3 represents how engineered T-cells (by CARs ( ) can be usedtherapeutically by engineering cells from the patient's own body andinfusing the T-cell back into the patient.

In BiTEs two single chain variable fragments are bound by a linker, oneScFv binds a tumor antigen and the other binds a tumor antigen,activating T cells and bringer closer them to the tumor cell, theantibody binds CD3 activating the T cell and the other just bind thetumor cell

SUMMARY

An aspect is technology that would allow the use of a CAR or BiTEproduced with a scFv from a humanized or non-human mammal (such asmouse) monoclonal antibody to TK1, that could be used with appropriategenetic engineering to manipulate lymphocytes (possibly T cells but mayinclude other immune cells) ultimately from a patient but not limited tosuch, to treat a disease such as cancer. That fact that TK1 is on thesurface of cancer cells and not on the surface of any normal cell is amajor part of the discovery, as this knowledge can be used to allow theT cells to be directed specifically to the tumor cells.

Another aspect lies in the fact that using our specifically generatedantibodies to human TK1 we have discovered that TK1 is expressed on thesurface of human cancer cells and not on the surface of normal cells andthereby can be used to target CARs and BiTEs to the tumors.

As aspect is CARs and BiTEs using the monoclonal antibodies, such as BYU74 BYU 72 and CB 001 that we have developed that bind specifically toTK1 on the surface of cancer cells. Antibodies specific to human TK1 aredisclosed in U.S. patent application Ser. No. 12/982,250, and U.S. Pat.Nos. 7,837,998, 7,311,906, and 5,698,409, which are hereby incorporatedby reference, and F. Zhang, X. Shao, J. G. Robison, B. K. Murray, and K.L. O'Neill. Hybridoma. February 2001, 20(1): 25-34.doi:10.1089/027245701300060382.

The CARs technology and BiTEs technology used disclosed herein can beused to modify macrophages as well as T cells. This may be combined withmacrophage tissue-specific promoters directed toward the cancer tissueto eliminate targeting of TK1 is the blood serum and direct to TK1 oncell surfaces.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 A TK1 specific CAR T Cell recognizes a cancer cell using TK1 onthe surface as a target. CAR T cells become activated upon recognitionof the cancer cell inducing cell death by apoptosis and lysis.

FIG. 2, depicts a generalized prior-art BITEs.

FIG. 3 depicts a therapeutic method using engineered T cells.

FIG. 4 shows a portion of a CARs transduced T-cell.

FIG. 5 is a construct of the TK1 CAR T cell vector. Retroviral mediatedgene transfer. 293GPG human retroviral packaging cells are transfectedwith the vector of interest, which is packaged transiently in vesicularstomatitis virus (VSV) G pseudotyped particles. These particles are usedto deliver the vector to PG13 cells, which achieve stable packaging ofGALV pseudotyped particles that are suitable for infection of humanT-cells.

FIG. 6 shows a method for transduction illustrating the retroviralmediated gene transfer.

FIGS. 7A-7D Sequencing data for the TK1 CAR T cell DNA vector (SEQ IDNO: 1).

FIG. 8 shows the sequence of the TK1 T cell CAR protein as FIG. 5.Therein depicted are the amino acid sequence of the signal peptide (SEQID NO:2): the CB1 light chain (SEQ ID NO:3): the glycine-serine linker(SEQ ID NO:4) the CB1 heavy chain (SEQ ID NO:5): the CD8α hinge (SEQ IDNO:6); the CD28 costimulatory domain (SEQ ID NO:7): and the CD3 zetacostimulatory domain (SEQ ID NO:8).

FIG. 9 TK1 CAR T cell Nucleotide (SEQ ID NO:1) and protein sequence (SEQID NOs:2-8 linked in order) alignment.

DETAILED DESCRIPTION Example

This is a specific example of how CAR transduced T-cells can be made.

Reference is made to FIG. 4. A CARs transduced T-cells comprisesingle-chain variable fragments (scFv) from the variable region of amonoclonal antibody. In this example the monoclonal antibody is specificto human thymidine kinase 1 (TK1)

FIG. 5 is a schematic of a construct the signal peptide to which achimeric antigen receptor will be added, which protein will betranducted into the T-cells. It comprises an ectodomain signallingpeptide based upon CB1 chains (k light chain attached to the scFv) and yheavy chain), a hinge portion based upon CD8, and an endodomain withcostimulatory domains based upon CD28, CD3 zeta costimulatory proteinreceptors.

FIG. 6 illustrates a method for introducing any CAR protein bytransduction into a T-cell and can be used in the present process.Chimeric antigen receptors (CARs) are genetically delivered fusionmolecules that elicit T-cell activation upon binding of a native cellsurface molecule. These molecules can be used to generate a large numberof memory and effector T-cells that are capable of recognizing andattacking tumor cells. Most commonly, stable CAR expression is achievedin T-cells using retroviral vectors. In the method shown in FIG. 6,retroviral vectors are packaged in a two-step procedure. First, H29Dhuman retroviral packaging cells (a derivative of 293 cells) aretransfected with the vector of interest, which is packaged transientlyin vesicular stomatitis virus (VSV) G pseudotyped particles. Theseparticles are used to deliver the vector to PG13 cells, which achievestable packaging of gibbon ape leukemia virus (GALV)-pseudotypedparticles that are suitable for infection of human T-cells. The keyadvantage of the method reported here is that it robustly generatespolyclonal PG13 cells that are 100% positive for the vector of interest.This means that efficient gene transfer may be repeatedly achievedwithout the need to clone individual PG13 cells for experimentalpre-clinical testing. To achieve T-cell transduction, cells must firstbe activated using a non-specific mitogen. Phytohemagglutinin (PHA)provides an economic and robust stimulus to achieve this. After 48-72 h,activated T-cells and virus-conditioned medium are mixed inRetroNectin-coated plasticware, which enhances transduction efficiency.Transduced cells are analyzed for gene transfer efficiency by flowcytometry 48 h following transduction and may then be tested in severalassays to evaluate CAR function, including target-dependentcytotoxicity, cytokine production and proliferation. (SeeParente-Pereira A C, Wilkie S, van der Stegen S J C, Davies D M, MaherJ. Use of retroviral-mediated gene transfer to deliver and test functionof chimeric antigen receptors in human T-cells. J Biol Methods 2014;1(2):e7. doi: 10.14440/jbm.2014.30)

FIGS. 7A-7D illustrate the sequence of the DNA of the TK1 CAR T cellvector

FIG. 8 shows the protein sequence of the TK1 CAR T cell protein

FIG. 9 shows the TK1 CAR T cell Nucleotide and protein sequencealignment

While this invention has been described with reference to certainspecific embodiments and examples, it will be recognized by thoseskilled in the art that many variations are possible without departingfrom the scope and spirit of this invention, and that the invention, asdescribed by the claims, is intended to cover all changes andmodifications of the invention which do not depart from the spirit ofthe invention.

REFERENCES

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What is claimed is:
 1. A chimeric antigen receptor (CAR) comprising a single-chain variable fragment (scFv) specific for TK1 operatively linked to a signaling domain.
 2. The CAR of claim 1, wherein the signaling domain is a leukocyte signaling domain.
 3. The CAR of claim 1, wherein the signaling domain is a T-cell signaling domain.
 4. The CAR of claim 1, wherein the signaling domain is a monocyte signaling domain.
 5. The CAR of claim 1, wherein the signaling domain is a human signaling domain.
 6. The CAR of claim 1, wherein the scFv is specific for the C-terminal of TK1.
 7. A nucleic acid encoding a chimeric antigen receptor (CAR) comprising a single-chain variable fragment (scFv) specific for TK1 operatively linked to a signaling domain.
 8. The nucleic acid of claim 7, wherein the nucleic acid comprises SEQ ID NO:
 1. 